The present invention relates to an invention for controlling the power output of an internal combustion engine having an external ignition system and a fuel injection system. According to the method, the position of the accelerator pedal adjusts a control device which controls the opening function of at least one inlet valve that determines the charge during intake of the internal combustion engine, whereby the opening function is defined by valve stroke and duration of the open state of the valve. The control device determines the relative phase position of two camshafts operating normally at identical rpm, and the phase position determines the opening function of the inlet valve.
Internal combustion engines operating according to the aforementioned method, in general, are not provided with a throttle. A charge change is controlled with variable control of the inlet valve(s) as well as, optionally, of the outlet valves. With such a control method the charge change losses can be substantially reduced, and it is also possible to provide for a directed influence on the charge state and the charge composition within the cylinder so that reduced emissions within the untreated exhaust gas are achieved.
Numerous fully variable valve drives for control of the charge of internal combustion engines have been disclosed in the prior art because of the aforementioned advantages; however, in practice, they have not found acceptance yet. In British Patent Application 2 180 597 a valve drive for a reciprocating internal combustion engine is disclosed in which the opening camshaft and the closing camshaft cooperate with a rocker arm that is supported on a valve shaft of inlet valve. In order for the rocker arm to maintain a defined position when the inlet valve is in a closed position, a spring is provided which forces the rocker arm in constant contact to the cam contour of the two cam shafts. Thus, the rocker arm at times is removed from the valve shaft. This considerably complicates use of an automatic valve play compensation system. A further characteristic of the known cam drive is that the actual valve stroke corresponds to half the height of the cam which makes the cam drive bulky and limits it with respect to its rpm consistency. For changing the phase position between the camshafts, they are connected to one another with a coupling gear that comprises for the phase adjustment a coupling, actuated by the accelerator pedal, as a control device. Similarly to a throttle, which is mechanically connected to the accelerator pedal of conventional motors, the coupling takes over the charge control of the internal combustion engine. This results in the problem that the inlet valve must close approximately in the range of the upper dead center of the piston because, otherwise, the filling of the cylinder and thus the torque at low rpm would be disadvantageously affected.
For controlling ignition and injection, it is known to determine the amount of intake air taken in by the engine with a sensor for measuring the volume or mass of the intake air and to control the amount of fuel to be injected as a function of the measured signal. These known control methods have the disadvantage, especially during dynamic operation in which, due to the change of the throttle position or due to a fast rpm change, the pressure within the suction tube changes, that they are relatively imprecise because the measured signal does note provide sufficiently precise clues with regard to the amount of intake air flowing into a respective cylinder and the thus required fuel amount. This results in increased pollutant levels within the exhaust gas, increased fuel consumption, and driving errors.
It is therefore an object of the present invention to provide a method for controlling an internal combustion engine with external ignition system and fuel injection device with which method, for a reduced amount of pollutants within the exhaust gas, an increased torque and increased power output is possible.